Facilitation of increased locking range transistors

ABSTRACT

Transistors can be used for a variety of electronic-based applications. Therefore, transistor efficiency and performance is of importance. An apparatus is presented herein to increase the locking range of transistors by leveraging cross-coupled injection transistors in conjunction with symmetry injection transistors. The transistor efficiency can also be increase by reducing a parasitic capacitance associated with the components of the transistor.

RELATED APPLICATION

This patent application is a divisional of, and claims priority to, U.S.patent application Ser. No. 14/809,812, filed Jul. 27, 2015, andentitled, “FACILITATION OF INCREASED LOCKING RANGE TRANSISTORS”, theentirety of which application is hereby incorporated by referenceherein.

TECHNICAL FIELD

This disclosure relates generally to transistors. More specifically,this disclosure relates to increasing transistor performance.

BACKGROUND

A transistor is a semiconductor device used to amplify and switchelectronic signals and electrical power. It is composed of semiconductormaterial with at least three terminals for connection to an externalcircuit. A voltage or current applied to one pair of the transistor'sterminals changes the current through another pair of terminals. Becausethe controlled (output) power can be higher than the controlling (input)power, a transistor can amplify a signal. Some transistors are packagedindividually, but many are found embedded in integrated circuits.

Transistors are utilized for their ability to use a small signal appliedbetween one pair of its terminals to control a much larger signal atanother pair of terminals. This property is called gain. It can producea stronger output signal, a voltage, or current, that is proportional toa weaker input signal; that is, it can act as an amplifier.Alternatively, the transistor can be used to turn current on or off in acircuit as an electrically controlled switch, where the amount ofcurrent is determined by other circuit elements.

There are two types of transistors, which have slight differences in howthey are used in a circuit. A bipolar transistor has terminals labeledbase, collector, and emitter. A small current at the base terminal (thatis, flowing between the base and the emitter) can control or switch amuch larger current between the collector and emitter terminals. For afield-effect transistor, the terminals are labeled gate, source, anddrain, and a voltage at the gate can control a current between sourceand drain.

The above-described background relating to transistors is merelyintended to provide a contextual overview of transistors, and is notintended to be exhaustive. Other context regarding transistors maybecome further apparent upon review of the following detaileddescription.

SUMMARY

A simplified summary is provided herein to help enable a basic orgeneral understanding of various aspects of exemplary, non-limitingembodiments that follow in the more detailed description and theaccompanying drawings. This summary is not intended, however, as anextensive or exhaustive overview. Instead, the purpose of this summaryis to present some concepts related to some exemplary non-limitingembodiments in simplified form as a prelude to more detailed descriptionof the various embodiments that follow in the disclosure.

The objective of the disclosure is to develop a means for increasing alocking range of a transistor. The locking range of the transistor canbe the frequency range of a frequency divider in a phase-locked loop(PLL) for which it is able to stay locked, and can be defined by avoltage controlled oscillator (VCO) range. A phase--lock loop can be acontrol system that generates an output signal whose phase is related tothe phase of an input signal. The oscillator can generate a periodicsignal. The phase detector can compare the phase of that signal with thephase of the input periodic signal and adjust the oscillator to keep thephases matched. Bringing the output signal back toward the input signalfor comparison can be defined as a feedback loop since the output can be‘fed back’ toward the input forming a loop.

Keeping the input and output phase in lock step can also keep the inputand output frequencies the same. Consequently, in addition tosynchronizing signals, a phase--locked loop can track an inputfrequency, or it can generate a frequency that is a multiple of theinput frequency. These properties can be used for computer clocksynchronization, demodulation, and frequency synthesis.

Phase-locked loops are widely employed in radio,telecommunications,computers and other electronic applications. They can be used todemodulate a signal, recover a signal from a noisy communicationchannel, generate a stable frequency at multiples of an input frequency(frequency synthesis), or distribute precisely timed clock pulses indigital logic circuits such as microprocessors. Since a singleintegrated circuit can provide a complete phase-locked-loop buildingblock, the technique is widely used in modern electronic devices, withoutput frequencies from a fraction of a hertz up to many gigahertz(GHz).

A parasitic capacitance is an unavoidable and usually unwantedcapacitance that exists between the parts of an electronic component orcircuit simply because of their proximity to each other. A low-parasiticand common-centroid transistor structure injection-locked frequencydivider (ILFD) can allow simple routing, minimize the parasiticcapacitances and resistances of interconnects, reduce source anddrain-to-body parasitic capacitances, and provide inherentcommon-centroid characteristic, all of which are conducive to improvinga high-frequency and wide locking range performance of complementarymetal-oxide-semiconductor (CMOS) ILFDs. The proposed transistorstructure can be applied for a 60 GHz ILFD design, which can dissipate7.5 mA from 0.5 V supply using 65 nm CMOS technology. The proposed ILFDcan demonstrate a 16.9 GHz locking range and can operate in 53.8-70.7GHz without a tuning mechanism.

This disclosure can be applied to the first stage of a frequency dividerchain in a high frequency PLL system. Since frequencies around 60 GHzhave been opened for unlicensed applications, such PLL systems can beused in the front-end systems of gigabits/point-to-point links, wirelesslocal area networks, high data-rate wireless personal area networks andradars. ILFDs can have low power consumption and high frequencycapability in CMOS technologies. However, ILFDs can suffer from narrowlocking ranges. Varactors can be used in ILFDs to increase the lockingrange, but the controlling voltages between the varactors in both theVCO and divider will need to be synchronized, which can significantlyincrease design complexity with a PLL system design. The currentdisclosure can use symmetry injection transistors with a sourceconnected to a ground to place all active devices in a standard radiofrequency (RF) transistor cell. The symmetry injection structure canincrease the injection current and the injection time during everyperiod, which can increase the locking range. All the active devices inan ILFD core can be built on a standard transistor cell, which canreduce the parasitic capacitance of the inductor-capacitor (LC) tank andalso increase the operation frequency of ILFD and the locking range.

There are several advantages of the proposed ILFD over existing ILFDwhere the locking range is the largest one at a 60 GHz frequency bandwithout a tuning mechanism. Therefore, the wide operating frequencyrange of the ILFD can cover the inevitable shift of the center operatingfrequency caused by the process variations in the small values ofintegrated spiral inductance or parasitic capacitance. Lack of a tuningmechanism can simplify the control of PLL between VCO and ILFD.

Described herein are systems, methods, articles of manufacture, andother embodiments or implementations that can facilitate the increase oftransistor performance and can be implemented in connection with anytype of radio, telecommunications, computer, and other electronicapplications device.

According to one embodiment, described herein is an apparatus forfacilitating increased transistor performance by increasing a lockingrange and reducing a parasitic capacitance. The apparatus can comprisecross-coupled injection transistors, symmetry injection transistors, andinterconnecting nodes, wherein the interconnecting nodes connectsources, drains, and gates of their respective injection transistors.

According to another embodiment, described herein is a method forfacilitating a four terminal transistor. The method can comprisefacilitating four transistors comprising two cross coupled transistorsand two symmetry injection transistors into a standard radio frequencytransistor cell. The cross coupled transistors' sources can be tied to aground, whereas gates of the symmetry injection transistors can be tiedto a terminal and the sources of the symmetry injection transistors canbe tied to ground too.

According to yet another embodiment, described herein is an apparatusfor facilitating increased transistor performance by increasing alocking range and reducing a parasitic capacitance. The apparatus cancomprise cross-coupled injection transistors, symmetry injectiontransistors, and interconnecting nodes, wherein the interconnectingnodes comprise three sources, two drains, and four gates.

These and other embodiments or implementations are described in moredetail below with reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments of the subject disclosureare described with reference to the following figures, wherein likereference numerals refer to like parts throughout the various viewsunless otherwise specified.

FIG. 1 illustrates an example schematic direct injection metal-oxidesemiconductor transistor.

FIG. 2 illustrates an example schematic of a symmetry injection-lockedfrequency divider apparatus.

FIG. 3 illustrates an example schematic of a four terminal transistor.

FIG. 4 illustrates an example schematic of an input sensitivity curvefor an injection-locked frequency divider apparatus.

FIG. 5 illustrates an example schematic of a phase noise graph of aninjection-locked frequency divider apparatus.

FIG. 6 illustrates an example method for forming four transistors onto atransistor cell.

FIG. 7 illustrates an example schematic of a system block diagram of amethod for forming four transistors onto a transistor cell comprisingconnecting symmetry injection transistor sources to a ground.

FIG. 8 illustrates an example schematic of a system block diagram of asymmetry injection-locked frequency divider comprising three sources,two drains, and four gates.

FIG. 9 illustrates an example schematic of a system block diagram of asymmetry injection-locked frequency divider comprising three sources,two drains, and four gates, wherein the third source comprises a ground.

FIG. 10 illustrates an example schematic of a system block diagram of asymmetry injection-locked frequency divider comprising three sources,two drains, and four gates, wherein the first symmetry injectiontransistor and the second symmetry injection transistor are PMOStransistors.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth toprovide a thorough understanding of various embodiments. One skilled inthe relevant art will recognize, however, that the techniques describedherein can be practiced without one or more of the specific details, orwith other methods, components, materials, etc. In other instances,well-known structures, materials, or operations are not shown ordescribed in detail to avoid obscuring certain aspects.

Reference throughout this specification to “one embodiment,” or “anembodiment,” means that a particular feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment. Thus, the appearances of the phrase “in oneembodiment,” “in one aspect,” or “in an embodiment,” in various placesthroughout this specification are not necessarily all referring to thesame embodiment. Furthermore, the particular features, structures, orcharacteristics may be combined in any suitable manner in one or moreembodiments.

As utilized herein, terms “component,” “system,” “interface,” and thelike are intended to refer to a computer-related entity, hardware,software (e.g., in execution), and/or firmware. For example, a componentcan be a processor, a process running on a processor, an object, anexecutable, a program, a storage device, and/or a computer. By way ofillustration, an application running on a server and the server can be acomponent. One or more components can reside within a process, and acomponent can be localized on one computer and/or distributed betweentwo or more computers.

Further, these components can execute from various computer readablemedia having various data structures stored thereon. The components cancommunicate via local and/or remote processes such as in accordance witha signal having one or more data packets (e.g., data from one componentinteracting with another component in a local system, distributedsystem, and/or across a network, e.g., the Internet, a local areanetwork, a wide area network, etc. with other systems via the signal).

As another example, a component can be an apparatus with specificfunctionality provided by mechanical parts operated by electric orelectronic circuitry; the electric or electronic circuitry can beoperated by a software application or a firmware application executed byone or more processors; the one or more processors can be internal orexternal to the apparatus and can execute at least a part of thesoftware or firmware application. As yet another example, a componentcan be an apparatus that provides specific functionality throughelectronic components without mechanical parts; the electroniccomponents can include one or more processors therein to executesoftware and/or firmware that confer(s), at least in part, thefunctionality of the electronic components. In an aspect, a componentcan emulate an electronic component via a virtual machine, e.g., withina cloud computing system.

The words “exemplary” and/or “demonstrative” are used herein to meanserving as an example, instance, or illustration. For the avoidance ofdoubt, the subject matter disclosed herein is not limited by suchexamples. In addition, any aspect or design described herein as“exemplary” and/or “demonstrative” is not necessarily to be construed aspreferred or advantageous over other aspects or designs, nor is it meantto preclude equivalent exemplary structures and techniques known tothose of ordinary skill in the art. Furthermore, to the extent that theterms “includes,” “has,” “contains,” and other similar words are used ineither the detailed description or the claims, such terms are intendedto be inclusive—in a manner similar to the term “comprising” as an opentransition word—without precluding any additional or other elements.

As used herein, the term “infer” or “inference” refers generally to theprocess of reasoning about, or inferring states of, the system,environment, user, and/or intent from a set of observations as capturedvia events and/or data. Captured data and events can include user data,device data, environment data, data from sensors, sensor data,application data, implicit data, explicit data, etc. Inference can beemployed to identify a specific context or action, or can generate aprobability distribution over states of interest based on aconsideration of data and events, for example.

Inference can also refer to techniques employed for composinghigher-level events from a set of events and/or data. Such inferenceresults in the construction of new events or actions from a set ofobserved events and/or stored event data, whether the events arecorrelated in close temporal proximity, and whether the events and datacome from one or several event and data sources. Various classificationschemes and/or systems (e.g., support vector machines, neural networks,expert systems, Bayesian belief networks, fuzzy logic, and data fusionengines) can be employed in connection with performing automatic and/orinferred action in connection with the disclosed subject matter.

In addition, the disclosed subject matter can be implemented as amethod, apparatus, or article of manufacture using standard programmingand/or engineering techniques to produce software, firmware, hardware,or any combination thereof to control a computer to implement thedisclosed subject matter. The term “article of manufacture” as usedherein is intended to encompass a computer program accessible from anycomputer-readable device, computer-readable carrier, orcomputer-readable media. For example, computer-readable media caninclude, but are not limited to, a magnetic storage device, e.g., harddisk; floppy disk; magnetic strip(s); an optical disk (e.g., compactdisk (CD), a digital video disc (DVD), a Blu-ray Disc™ (BD)); a smartcard; a flash memory device (e.g., card, stick, key drive); and/or avirtual device that emulates a storage device and/or any of the abovecomputer-readable media.

As an overview of the various embodiments presented herein, to correctfor the above-identified deficiencies and other drawbacks ofconventional direct injection scheme, various embodiments are describedherein to facilitate increase transistor performance.

FIGS. 1-12 illustrate apparatuses and methods that can increasetransistor performance by facilitating an increased locking range. Forsimplicity of explanation, the methods (or algorithms) are depicted anddescribed as a series of acts. It is to be understood and appreciatedthat the various embodiments are not limited by the acts illustratedand/or by the order of acts. For example, acts can occur in variousorders and/or concurrently, and with other acts not presented ordescribed herein. Furthermore, not all illustrated acts may be requiredto implement the methods. In addition, the methods could alternativelybe represented as a series of interrelated states via a state diagram orevents. Additionally, the methods described hereafter are capable ofbeing stored on an article of manufacture (e.g., a computer readablestorage medium) to facilitate transporting and transferring suchmethodologies to computers. The term article of manufacture, as usedherein, is intended to encompass a computer program accessible from anycomputer-readable device, carrier, or media, including a non-transitorycomputer readable storage medium.

Referring now to FIG. 1, illustrated is an example schematic directinjection metal-oxide semiconductor (MOS) transistor 100. A conventionaldirect injection scheme based on a MOS transistor switch over the tankis shown in FIG. 1. The injection-locked oscillator can comprise across-coupled n-channel MOS pair 102, a center-taped inductor 104, and adirect injection transistor 106. An LC tank can absorb a parasiticcapacitance into a resonator. The direct injection MOS transistor cancomprise the parasitic capacitance of the cross-coupled NMOS pair 102,the parasitic capacitance of the direct injection transistor 106, a loadcapacitance of a next stage, and the parasitic capacitance of aninterconnected metal path. For measurement purposes, the locking range,Δω, can be determined by Eqn. 1 below:

$\begin{matrix}{{{\Delta\omega}}_{{ma}\; x} \propto {\frac{\alpha_{2}V_{i}}{C}}} & \left( {{Eqn}.\mspace{14mu} 1} \right)\end{matrix}$

where V_(i) can be the amplitude of the input signal, α₂ can be thesecond order nonlinear coefficient of the injection transistor, and Ccan be the capacitance of the resonator. Therefore, the locking rangecan be improved by reducing the parasitic capacitors.

The direct current (DC) voltage at the source and drain terminals ofinjection transistor M3 is a voltage generated by a supply voltage(VDD). If the voltage bias (Vbias) at the gate terminal of M3 is alsoVDD, then the time M3 is “on” is less than half of a period an injectionsignal. Meanwhile, the parasitic capacitance at the source of M3 can bedifferent than that of the drain. This asymmetry can make it difficultto improve the performance of the ILFD. Therefore, to improve thelocking range of the ILFD, the parasitic capacitance of the LC tankshould be minimized. The second important dependency of locking rangecan be on the injection power, the improvement of which can increase thelocking range.

Referring now to FIG. 2, illustrated is an example schematic of asymmetry injection-locked frequency divider apparatus. FIG. 2 shows aproposed symmetry ILFD schematic. The symmetry ILFD can employ twoinjection transistors 206 208 with sources connected to a ground 216, sothat the injection transistors 206 208 “on” time is more than half ofthe period of the injection signal. The injection current can also bebigger than that of the conventional direct injection transistor.However, for the same transconductance amplifier (g_(m)) duringinjection, the size of the symmetry ILFD structure could be twice sizeof that of the single transistor in FIG. 1, which can induce additionalparasitic capacitance and reduce the locking range.

For conventional RF NMOS transistor structures, each transistor can beplaced in a cell with circulating body and a deep N-well. Since thetransistors are generally spaced apart from each other, a density of theimpurities implanted into the gate area varies from one area to theother. Therefore a threshold voltage difference can occur amongst thesetransistors, which can also cause asymmetry, and the circuit may notoperate as designed.

The symmetry ILFD of FIG. 2 can comprise cross-coupled NMOS transistors202 204, and symmetry injection transistors 206 208, which share commonnodes and the source terminals are connected to a ground 216. Thesymmetry ILFD also comprises a drain of the cross-coupled NMOStransistor 202, a gate of the cross-coupled NMOS transistor 204, a drainof symmetry injection transistors 206, which are tied to a node 210.Furthermore, the symmetry ILFD can comprise a drain of the cross-coupledNMOS transistor 204, a gate of the cross-coupled NMOS transistor 202,and a drain of the symmetry injection transistor 208, which are tied toa node 212. The gates of the symmetry injection transistors 206 208 aretied to a node 214. Therefore, the transistors can share drain terminalsto reduce the parasitic junction capacitance in the following manner.

A first injection transistor 202 can comprise a first source. A secondinjection transistor 204 can comprise a second source, wherein the firstinjection transistor 202 and the second injection transistor 204 can becross coupled, and wherein the first source and the second source can beconnected to a first ground 216. The cross-connection of the firstinjection transistor 202 and the second injection transistor 204 can bethe only cross-connection, which can limit parasitic capacitance. Afirst symmetry injection transistor 206 can comprise a third source, anda second symmetry injection transistor 208 can comprise a fourth source,wherein the third source and the fourth source can be connected to asecond ground 218. The first symmetry injection transistor 206 and thesecond symmetry injector transistor 208 can share a common node and allof the source terminals can be connected to the second ground 218. Afirst node 210 can comprise a first drain of the first injectiontransistor 202, a first gate of the second injection transistor 204, anda second drain of the first symmetry injection transistor 206. A secondnode 212 can comprise a third drain of the second injection transistor204, a second gate of the first injection transistor 202, and a forthdrain of the second symmetry injection transistor 208. A third node 214can comprise a third gate of the first symmetry injection transistor206, and a fourth gate of the second symmetry injection transistor 208.

Referring now to FIG. 3, illustrated is an example schematic of a fourterminal transistor. FIG. 3 is representative of an example reconfigured4-terminal transistor, as shown in FIG. 2, when the widths and gatenumbers of the transistors 202 204 206 208 are the same. The majorlayers in a CMOS process can be referenced in the legend of FIG. 3 asfollows: NW is N-type well layer, PW is P-type well, OD is thin oxidefor device, PO is poly-Si for the gate of transistor, CO is the contactwindow form transistor 202 to OD or PO, MM1 is the first metal layer,VIA1 is the contact hole between MM2 and MM1, MM2 is the second metallayer, VIA2 is the contact hole between MM3 and MM2, and MM3 is thethird metal layer.

The reconfigured transistor can comprise three sources S1, S2 and S3,two drains D1 and D2 and four gates G1, G2, G3, and G4. The drain oftransistors 202 206 and the gate of transistor 204 can be directlyconnected to the node 210 through contact with VIA1 and metal layers andthen leave the transistor cell. The drain of transistors 204 208 and thegate of transistor 202 can be directly connected to the node 212 throughcontact with VIA1 and metal layers and then leave the transistor cell.The gates of the transistors 206 208 can be directly connected to thenode 214 through contact with the poly layer and then leave thetransistor cell.

If using the traditional method (individual transistor) to perform thesame layout, there has four individual sources and drains need to beconnected. Leveraging the reconfigured transistor, can use half of thedrains of the transistors 206 208 being connected, whereas thetraditional method requires four individual sources and drains of thetransistors to be connected. In addition, the gate-drain crossconnection of the transistors 202 204 involves no additional routing andoverlapping of interconnects. Therefore, parasitic capacitance can beminimized from the nodes 219 214 and the nodes 212 214. Thus, thereconfigured transistor the layout of the ILFD can be simplified toreduce parasitic capacitance and improve the locking range of the ILFD.

Referring now to FIG. 4, illustrated is an example schematic of an inputsensitivity curve for an injection-locked frequency divider apparatus.FIG. 4 comprises an input power versus a frequency of a frequencydivider circuit, which can result from a circuit simulation. The biasvoltage can be set to 0.5 V, which can be equal to the power supply. TheILFD circuit can operate with a maximum input signal frequency at 70.7GHz, and a minimum input signal frequency at 53.8 GHz. Thus, the ILFDcircuit can operate at a center frequency of 62.25 GHz with a frequencylocking range of approximately 27.15%.

Referring now to FIG. 5, illustrated is an example schematic of a phasenoise graph of an injection-locked frequency divider apparatus. FIG. 5illustrates a graph plot of a phase noise versus an offset frequency ofthe ILFD under a condition that the input signal can be in an idle stateand receive no input signal. As shown, when the offset frequency is 1MHz, the phase noise can be approximately −99.9 dBc/Hz.

Referring now to FIG. 6, illustrated is an example method for formingfour transistors onto a transistor cell. At element 600 a four-terminaltransistor comprising a first injection transistor and a secondinjection transistor and a first symmetry injection transistor and asecond symmetry injection transistor can be formed. At element 602 afirst drain of the first injection transistor, a second drain of thefirst symmetry injection transistor, and a first gate of the secondinjection transistor can be connected to a first terminal. Thetransistors can share drain terminals parasitic junction capacitances. Asecond gate of the first symmetry injection transistor and a third gateof the second symmetry injection can be connected to a second terminalat element 604. Further, at element 606 a third drain of the secondinjection transistor, a fourth drain of the second symmetry injectiontransistor, and a fourth gate of the second injection transistor can beconnected to a third terminal. At element 608 the first drain of thefirst injection transistor can be cross-connected with the first gate ofthe second injection transistor; and the third drain of the secondinjection transistor can be cross-connected with the fourth gate of thefirst injection transistor at element 610.

Referring now to FIG. 7, illustrated is an example schematic of a systemblock diagram of a method for forming four transistors onto a transistorcell comprising connecting symmetry injection transistor sources to aground. At element 700 a four-terminal transistor comprising a firstinjection transistor and a second injection transistor and a firstsymmetry injection transistor and a second symmetry injection transistorcan be formed. At element 702 a first drain of the first injectiontransistor, a second drain of the first symmetry injection transistor,and a first gate of the second injection transistor can be connected toa first terminal. The transistors can share drain terminals parasiticjunction capacitances. A second gate of the first symmetry injectiontransistor and a third gate of the second symmetry injection can beconnected to a second terminal at element 704. Further, at element 706 athird drain of the second injection transistor, a fourth drain of thesecond symmetry injection transistor, and a fourth gate of the secondinjection transistor can be connected to a third terminal. At element908 the first drain of the first injection transistor can becross-connected with the first gate of the second injection transistor;and the third drain of the second injection transistor can becross-connected with the fourth gate of the first injection transistorat element 710. At element 712, a first source of the first symmetryinjection transistor and a second source of the second symmetryinjection transistor can be connect to a ground.

Referring now to FIG. 8, illustrated is an example schematic of a systemblock diagram of a symmetry injection-locked frequency dividercomprising three sources, two drains, and four gates. At element 800, afirst injection transistor comprising a first source can be formed. Atelement 802, a second injection transistor comprising a second sourcecan be formed, wherein the first injection transistor and the secondinjection transistor can be cross coupled, and wherein the first sourceand the second source can be connected to a first ground. Thecross-connection of the first injection transistor and the secondinjection transistor can be the only cross-connection, which can limitparasitic capacitance. At element 804, a first symmetry injectiontransistor can be formed, and a second symmetry injection transistor canbe formed at element 806, wherein the first symmetry injectiontransistor and the second symmetry injection transistor share a thirdsource. At element 808, a first node can be formed that can comprise afirst gate of the second injection transistor at element 810 and cancomprise a first drain, wherein the first injection transistor and thefirst symmetry injection transistor can share the first drain at element812. At element 814, a second node can be formed that can comprise asecond gate of the first injection transistor at element 816 and asecond drain, wherein the second injection transistor and the secondsymmetry injection transistor share the second drain at element 818. Atelement 820, a third node can be formed that can comprise a third gateof the first symmetry injection transistor at element 822 and a fourthgate of the second symmetry injection transistor at element 824.

Referring now to FIG. 9, illustrated is an example schematic of a systemblock diagram of a symmetry injection-locked frequency dividercomprising three sources, two drains, and four gates wherein the thirdsource comprises a ground. At element 900, a first injection transistorcomprising a first source can be formed. At element 902, a secondinjection transistor comprising a second source can be formed, whereinthe first injection transistor and the second injection transistor canbe cross coupled, and wherein the first source and the second source canbe connected to a first ground. The cross-connection of the firstinjection transistor and the second injection transistor can be the onlycross-connection, which can limit parasitic capacitance. At element 904,a first symmetry injection transistor can be formed, and a secondsymmetry injection transistor can be formed at element 906, wherein thefirst symmetry injection transistor and the second symmetry injectiontransistor share a third source.

At element 908, a first node can be formed that can comprise a firstgate of the second injection transistor at element 910 and can comprisea first drain, wherein the first injection transistor and the firstsymmetry injection transistor can share the first drain at element 912.At element 914, a second node can be formed that can comprise a secondgate of the first injection transistor at element 916 and a seconddrain, wherein the second injection transistor and the second symmetryinjection transistor share the second drain at element 918. At element920, a third node can be formed that can comprise a third gate of thefirst symmetry injection transistor at element 922 and a fourth gate ofthe second symmetry injection transistor at element 924. Further, thethird source can comprise a ground at element 926.

Referring now to FIG. 10, illustrated is an example schematic of asystem block diagram of a symmetry injection-locked frequency dividercomprising three sources, two drains, and four gates wherein the firstsymmetry injection transistor and the second symmetry injectiontransistor can be p-type metal-oxide-semiconductor field-effect (PMOS)transistors. At element 1000, a first injection transistor comprising afirst source can be formed. At element 1002, a second injectiontransistor comprising a second source can be formed, wherein the firstinjection transistor and the second injection transistor can be crosscoupled, and wherein the first source and the second source can beconnected to a first ground. The cross-connection of the first injectiontransistor and the second injection transistor can be the onlycross-connection, which can limit parasitic capacitance.

At element 1004, a first symmetry injection transistor can be formed,and a second symmetry injection transistor can be formed at element1006, wherein the first symmetry injection transistor and the secondsymmetry injection transistor share a third source. At element 1008, afirst node can be formed that can comprise a first gate of the secondinjection transistor at element 1010 and can comprise a first drain,wherein the first injection transistor and the first symmetry injectiontransistor can share the first drain at element 1012. At element 1014, asecond node can be formed that can comprise a second gate of the firstinjection transistor at element 1016 and a second drain, wherein thesecond injection transistor and the second symmetry injection transistorshare the second drain at element 1018. At element 1020, a third nodecan be formed that can comprise a third gate of the first symmetryinjection transistor at element 1022 and a fourth gate of the secondsymmetry injection transistor at element 1024. Furthermore, the firstsymmetry injection transistor and the second symmetry injectiontransistor can be PMOS transistors at element 1026.

The above description of illustrated embodiments of the subjectdisclosure, including what is described in the Abstract, is not intendedto be exhaustive or to limit the disclosed embodiments to the preciseforms disclosed. While specific embodiments and examples are describedherein for illustrative purposes, various modifications are possiblethat are considered within the scope of such embodiments and examples,as those skilled in the relevant art can recognize.

In this regard, while the subject matter has been described herein inconnection with various embodiments and corresponding FIGs, whereapplicable, it is to be understood that other similar embodiments can beused or modifications and additions can be made to the describedembodiments for performing the same, similar, alternative, or substitutefunction of the disclosed subject matter without deviating therefrom.Therefore, the disclosed subject matter should not be limited to anysingle embodiment described herein, but rather should be construed inbreadth and scope in accordance with the appended claims below.

What is claimed is:
 1. A method, comprising: forming a four-terminaltransistor comprising a first injection transistor and a secondinjection transistor and a first symmetry injection transistor and asecond symmetry injection transistor; connecting a first drain of thefirst injection transistor, a second drain of the first symmetryinjection transistor, and a first gate of the second injectiontransistor to a first terminal; connecting a second gate of the firstsymmetry injection transistor and a third gate of the second symmetryinjection to a second terminal; connecting a third drain of the secondinjection transistor, a fourth drain of the second symmetry injectiontransistor, and a fourth gate of the second injection transistor to athird terminal; cross-connecting the first drain of the first injectiontransistor with the first gate of the second injection transistor; andcross-connecting the third drain of the second injection transistor withthe fourth gate of the first injection transistor.
 2. The method ofclaim 1, further comprising: connecting a first source of the firstsymmetry injection transistor and a second source of the second symmetryinjection transistor to a ground.
 3. The method of claim 2, furthercomprising: connecting a third source of the first injection transistorand a fourth source of the second injection transistor to anotherground.
 4. The method of claim 1, further comprising: connecting a firstsource of the first injection transistor and a second source of thesecond injection transistor to a ground.
 5. The method of claim 1,wherein the forming comprises integrating the first injectiontransistor, the second injection transistor, the first symmetryinjection transistor, and the second symmetry injection transistor intoa standard radio frequency transistor cell.
 6. The method of claim 1,further comprising: connecting the first terminal and the third terminalto an inductor.
 7. The method of claim 6, wherein the inductor comprisesan electrical contact at a midpoint of the inductor.
 8. A method,comprising: forming a first injection transistor comprising a firstsource; forming a second injection transistor comprising a secondsource, wherein the first injection transistor and the second injectiontransistor are cross coupled, and wherein the first source and thesecond source are connected to a first ground; forming a first symmetryinjection transistor; forming a second symmetry injection transistor,wherein the first symmetry injection transistor and the second symmetryinjection transistor share a third source; forming a first nodecomprising: a first gate of the second injection transistor; and a firstdrain, wherein the first injection transistor and the first symmetryinjection transistor share the first drain; forming a second nodecomprising: a second gate of the first injection transistor; and asecond drain, wherein the second injection transistor and the secondsymmetry injection transistor share the second drain; and forming athird node comprising: a third gate of the first symmetry injectiontransistor; and a fourth gate of the second symmetry injectiontransistor.
 9. The method of claim 8, wherein the third source comprisesa ground.
 10. The method of claim 8, wherein the first symmetryinjection transistor and the second symmetry injection transistor arep-type metal-oxide-semiconductor field-effect transistors.
 11. Themethod of claim 8, wherein the first injection transistor and the secondinjection transistor are p-type metal-oxide-semiconductor field-effecttransistors.